Model Engineer Beam Engine - Reeves Kit

[propforward]

Finally back to making an actual engine.

This is one of "the usual offerings" so likely not very interesting to the elite but I'm doing it anyway. I think the ME Beam is a very pretty engine when finished, with quite a lot going on. As a basis I am using the Reeves offering of castings, which I purchased about 2 years ago I think. My initial look over the castings says they are OK - not warped or twisted or anything so I'm looking forward to an enjoyable, completely trouble free and relaxing experience. 

Don't worry, I can usually steer myself down paths that bring their own trouble and woes.

So all I've done so far is spend some time with the base plate. As seems normal on casting kits, the way the parts are dimensioned is largely inappropriate, and if not interpreted correctly could steer the unwary quite wrong I think.

For now all I've done is best condition the casting and skim the underside flat. Hey - it's a start. this done in such a way as to maintain enough machining stock on the top side features to get everything where it needs to be.

Best conditioning is the term we used at my last job to essentially balance the set up of a weldment or casting for the best combination of maximum machining stock on all features that get machined, while at the same time not distorting the part with clamping, and then also maintaining visual appeal as needed. What it means in this case is that I measured the casting all over as well as probing it with a height gauge on my surface plate to figure out how twisted / distorted it was. In reality actually pretty decent - about 25 thou variation across the main surface that is to be unfinished, same on the underside, with about 1/16" of stock on most surfaces, so pretty easy to level up and get going on.

The numbers on the casting represent height differences in thousandths of an inch from one corner.



Then up on the mill and skimmed the underside a few thou at a time until it cleaned up. I'd established that the center square feature where the column goes is actually the least out of flat, and indeed that resulted in only skimming about .020" off the highest point to get full clean up. I supported the part on a couple of machinist jacks as well to stop it flexing during cutting. It was a bit of a lightly clamped set up so I just took it really easy. After checking the finished cut on the surface plate there is no rock, so now I can get it clamped really well, best condition it on the table and start on real features.



Not much of a start - on the other hand quite the setting of the foundation.

I see I need to get back into the swing of taking pictures as I go. Blasted YouTube channel has me focusing more on that than still pics. In due course there will be video offerings as well but man they take some work editing.

[simplyloco]

Finally back to making an actual engine.:

This is one of "the usual offerings" so likely not very interesting to the elite.

No such movement on this forum. Good luck with your build and I look forward to seeing your progress.
JB

[propforward]

Thank you. Hopefully I can do it justice. I always start off with big ideas and end up having to make compromises.

[Michael S.]

A good start.
I'm watching with great interest because I also want to build this engine.

Michael

[propforward]

Stumbling forward at a breakneck pace, I actually clamped the base to the mill table tonight. It is clamped on top of a sacrificial aluminium plate which has been skimmed flat on both sides.




In order to get it lined up and ready I indicated the 4 red surfaces (edges) of the raised square, and the two long sides (blue).




I didn't drag the indicator - just went in and touched at several points along these edges, checking the DRO for offset. The part is basically within .005 along each of these 4 edges. They are surprisingly straight, which is why I used them. This is about as evenly set up as I can get it.

With it aligned, I will establish the center of the raised square in both the X and Y directions, and that will be the datum for drilling all the holes. Seems to me that basically everything on the engine is relative to the center of the beam column (and therefore beam pivot).

The heights of the various steps on the base will all be machined relative to the machined top of the square also. In this way, all these machined surfaces will be parallel to each other, so that everything is as square and true as it can be when assembled. What I am going for here, is an engine that runs without having to do much "bedding in".

So I started re-dimensioning the drawing to better show that and make for an easier reference. I did it long hand, by just doing the basic maths and writing it out on a copy of the drawing, but it started getting far too messy and I couldn't read my own writing.




It was more legible to make a basic model and show all the features using ordinates - and I can plot this out nice and big.







Also - I am using UNC and UNF threads instead of BA threads, just because of tap and fastener availability. I did a comparison of BA thread OD's and TPI numbers against the UNC and UNF series and found threads that are close enough. Not equivalent - they won't play together - they are just physically very similar in size. Should work out OK.

Then my evening of shed time ran out. So maybe tomorrow I can actually get some machining done. It's all in the prep anyway - do that right and the machining goes much more smoothly.

[Jasonb]

How does the casting compare with the drawings particularly lengthways? I'm not sure it was always supplied as an aluminium casting so the pattern may have been made to suit the shrinkage of iron.

[propforward]

Thanks for looking in Jason. It seems like the casting is on the large side, by between .03" and .05" depending on where and what is being measured. So small features are long / oversize by about .03", distances from center vary between .03 and .05 as you move further out. This is good from a height standpoint as it means there is a little more material to take off and keep everything correct, but it means a bit of thought needed for the hole patterns. If I just establish center of the square plinth and use that, then everything will work and all patterns will be aligned relative to each other, but the circular pattern on the cylinder boss will definitely not be concentric to the boss. May not be so important when everything is bolted in place.

Anyway, likely what I will do is split the difference between the square and round plinths. Once assembled that shouldn't show up particularly. I can always dust off the outsides of the cast features also, although I'd rather leave those as cast.

Likely putting too much effort into this balancing act but I enjoy it and ultimately should make for a nice fitting engine. Need to double check the beam casting before starting to make sure the bosses on that are close enough. I really don't want to alter engine dimensions though. I recall doing that when I first got the castings and don't recall any red flags, so should be OK.

The only thing that likely won't be made to print is the very outside dimensions, and locations of bolt down holes in the oval tabs. Those I will best fit to the cast features and merely dust off the outsides the minimum needed to clean and square it up. For sure if I went with drawing dims the outside would eat into the oval feature and several of the holes would be off visually.

Hoping to cut metal tonight - but a big trip coming up so I need to prep for that, so may be a week or two before this makes any real progress.

EDIT: The supplied plans show this as an iron casting, so yes indeed this is a change from original. Maybe because the iron one was too undersized and / or twisted? Also or maybe solely on cost.

[propforward]

Hehe - I see I've got a dimension snapped to the end of a center line rather than a hole center. A few things to check there before I cut anything! This is one of the pitfalls of redrawing stuff.

[Michael S.]

Hi Stuart, I don't know if my pictures will be of any use to you to check the size of the base. I don't know what year the aluminum base is from either.

Michael

[propforward]

Thank you Michael! I’ll do a comparison tonight. Looks like I’ll be able to get enough time to make start on actually cutting.

[propforward]

So next bit was simple enough really - touch off on the highest feature (having first measured heights of all the features to know what was to come off), fix the quill, touch off by raising the knee, establish the highest plane and raise the knee accordingly to clean off the other surfaces.

One feature had to be centered and machined on the width also to accept a bearing block later on.

This just shows my scratch where I recorded data about stock and heights etc.



Then the machined article. Ran out of time now so can't get the various holes in at the moment, but it's all set up well for that.





Hoping to be able to knock out a video on it in some down time later.

[crueby]

Nice start on the engine bed!   

[Roger B]

Off to a good start    I trust that the castings were well fondled before the first cuts  

[Michael S.]

The starting signal has been fired. Very nice!

Michael

[propforward]

Thanks all - as always I appreciate you looking in and also any comments. I'd also like to point out that I am very interested in what might be construed as negative feedback if it's presented fairly - as in alternative approaches or where I might be setting myself up for failure later on. It's a result of such feedback that I have managed to improve my techniques.

Also - a big THANK YOU to Michael, who behind the scenes has sent me some additional information he has acquired on this engine which is helping me determine the design intent behind some features, that are not immediately obvious from the Reeves plans. Also - the Reeves drawings have had a few details removed since the original ones were punlished.

Aaaaaaaaaaaaaaaaaaaaand here's the video, which explains better than the post what I am trying to do. Need to up my game on making detailed posts as well as improving my machining.


<a href="https://www.youtube.com/watch?v=VvIcZMrOlEo" target="_blank">http://www.youtube.com/watch?v=VvIcZMrOlEo</a>

[Jo]

Sorry 21 seconds into the video I realised how long this video is and the glass of wine won out

If you have a question you need answering you need to make it quickly clear so we can answer it.

Jo

[Jasonb]

Sorry 21 seconds into the video I realised how long this video is and the glass of wine won out

can't you multi-task?

[propforward]

I don’t have any questions. I’m documenting what I’m doing in the videos, that’s all.

[Jo]

Sorry 21 seconds into the video I realised how long this video is and the glass of wine won out

can't you multi-task?

Ask my ex husband    He's the one still working and I'm the one who is into my 7th year of retirement and struggling with the financial challenges   

Sorry for the side track Stuart   

Jo

[propforward]

That’s quite alright. A little sidetrack brings some interest and humanity. Otherwise it’s nothing but engines, engines, engines and splitting hairs over a fraction of a thousandth of an inch.

[propforward]

I got time to drill holes. If you want you can watch the process here. It’s just drilling holes. I’ve been kept from machining somewhat by freelance engineering so this is all I got to do for the last month.

Bonus! Shedland Christmas light show spectacular!

I will post still images later. But - it’s just holes drilled and tapped.

<a href="https://www.youtube.com/watch?v=6P0m_uZx2Jo" target="_blank">http://www.youtube.com/watch?v=6P0m_uZx2Jo</a>

[propforward]

Not much to it really. I did a minimum clean up of the main bearing mounting surface and also the pump mounting surface. the plans don't call for that but I want those surfaces parallel to the other machined surfaces, so that all the final engine components play nicely together.







With that done I mounted a drill chuck - a cheap (it wasn't that cheap) and nasty import chuck which had loads of run out in it - fixed by clamping the jaws of the chuck to a nice piece of drill rod in the lathe and then turning the shank lightly - and installed a center drill and went around my ordinate dimensions and pecked every drill location. That was simply to look at the pattern and see if it was centered well enough on the casting.

I didn't take a pic of the pattern. 

I was happy enough with it - it looks well located overall. The patterns on the round boss are shifted relative to the boss center by about .015 in the X and .020 in the Y, which is easy to see by eye. I think this boss will be completely covered in assembly and not noticeable. If it is noticeable I may put the casting on my rotary table and lightly skim the diameter just to true it up.

Then, happy with that, I went around and drilled and tapped.



Followed up by dusting off the outside edges of the base to make them straight and clean. I also cleaned the flash out of the openings in the base. Did all that by eye and by feel just to get the ugly off, as Joe Pie says.





And that's that for the time being.



I have a little hand fettling to do yet. I chose not to do the base mounting holes quite yet as I have not decided on the final presentation - although really what else am I going to do other than bolt it down through those bosses? Need to hand fettle them round first where I had to cut into them. Or maybe mill them off altogether all the way round - hence not worrying about drilling them quite yet.

[Michael S.]

Hello Stuart,

You did a perfect job with the base plate.
I would only drill the mounting holes into these cast elevations. Maybe mill a round surface with the milling cutter.
It's like that with large castings.

Michael

[Kim]

Great to see some progress on your beam engine! 

Kim

[Dave Otto]

Nice work, there is a lot going on there.

Dave

[propforward]

Thank you all. Not much there yet, but precision on this piece is certainly going to be important as more of it comes together. Even just drilling a lot of holes is great fun but I’m looking forward to more ornate looking parts.

Not sure what to tackle next, but need to wrap up this freelance thing first.

[scc]

Nice work             Terry

[MJM460]

That base plate is coming on nicely Stuart.  Enjoying every instalment.

MJM460

[Roger B]

Coming along nicely   

[propforward]

I made a thing.

I had some communications with a writer at Model Engineer, and was discussing the shortcomings of the base casting on this model. In the end, rather than wait until later, I went ahead and completely removed the circular boss and the two rails next to it. Those features are way off center and will look horrible if left in place.

As a result, I needed to either make the boss as a new disc on its own - or do as I ended up doing and incorporate the disc into the outboard head.

The head is a circular wedge shaped item - you can see it here in cross section, at the bottom of the cylinder.



I made mine like this, to replace the boss at the same time.



Before I go any further, I want to make it clear that the approach I have taken is one of achieving best accuracy I can, because I felt like it. The wedge feature can be achieved by simple marking out perfectly well - in fact I'm sure the engine would run fine if the head was just made with a flat, non angled face. I just decided to go this route because I find it satisfying.

So first off a piece of 2" steel rod went into the lathe. 2" is the largest diameter I can fit through the chuck and spindle, but that's pretty good - saved me having to saw off a lump and make more scrap. That was turned to a top hat shape at final OD of the part that fits in the cylinder - at .0005" under the nominal diameter of the mating bore (when I get to that).



Incidentally - and this is a bit extravagant but REALLY nice - the domestic authority desired a new TV in the house so I repurposed the "old" one as a monitor. It is in full view of lathe and mill. I didn't really think it would work out so well but it is unbelievably nice to have drawings magnified right there in view.



So then that was parted off, turned around and the dowel hole put in the back side.

And there is the top hat - all very simple. A fun bit of turning.



The next bit is the more interesting bit. But I have to take the dog for a walk first.

[Kim]

Very nice top hat! 

And I love your monitor!  That's a great use for a repurposed TV!  Nicely done!

Kim

[Michael S.]

Hello Stuart,
I'm glad you're continuing to work on the engine. The new cylinder head cover is a good idea.

When I place the cylinder head under the beam, it's also slightly off-center from the rounded space on the aluminum base.


Michael

[propforward]

Thanks Michael - a lot going on in life unfortunately, too many distractions from what I want to do but such is the way of things. Gradually getting those distractions out of the way.

Those off center features don't affect anything other than slight appearance - but I'm glad I did the clean up.

So, the fun bit is getting the angled face on it at the right height and clocked correctly to the bolt pattern. Not all that hard - and as mentioned, if one were to eyeball it and mark the height front and back, paint some blue on, scribe a line etc it would all work out.

But I decided to make a holding fixture out of a piece of scraptonium, including a mating dowel pin hole at the center, the bolt pattern in the head / ring and another dowel pin for a tooling ball. The tooling ball acts as an easy to establish reference, the holding fixture is then angled making use of a sine bar.

I’m changing all the BA threads over to UNC or UNF threads which are easier to deal with stateside. There are close enough sizes. Not equivalent – they won’t play together – just similar physical sizes. I tabulated the whole arrangement. I was surprised I couldn’t find anything already done, figured that must surely have been done and shared before.

Anyway – the fixture block was all squared up and the center hole drilled and reamed, and bolt pattern added. Here it is tapped with my home-made small tap holder.



The idea of using a tooling ball to establish location actually came to me after making the fixture to that point. My original plan had been to use a dowel pin, but it would have been difficult to keep perpendicular to the vise jaws. The tooling ball is easy – here is a reamed hole being added. I’m using a kool mist mainly to blow chips away so nothing gets jammed in the reamer to make the hole go oversize.



Tooling ball fitted – a nice close, slip fit.



So, this drawing helps to explain the point of the ball.



The drawing has the dimension from the top of the ball to the finished wedge surface – so now you can see that it is possible to set up the fixture in a vise on a sine plate, touch off an end mill on top of the ball (by way of a feeler gauge so as to not damage either end mill or ball), and then bring the tool down (actually the mill knee up) until dimension from top of the ball to finished surface is reached. Now the wedge is very accurately created.

Although I have CAD and it’s easy to measure the dimension needed, I like to do the trigonometry. I’ll show the triangles here and how that works for the fun of it. I feel like making the effort to do the maths increases overall understanding of geometry – and it’s just a bit of trigonometry. I drew this up to show the relevant calculations and geometry.



Hopefully that’s self-explanatory. For anyone interested in the details I will go through the calcs on the video I am putting together for this, but basically the numerical dimensions are the known values – dimensions desired on the final part etc, and the dimensions in letters are what have to be calculated to get the vertical dimension that references from the top of the tooling ball to the finished angled face, when the part is set up in the milling machine.
So OK – with that known here is the set up – using a sine bar to get the angle as accurate as possible. Yes – more trigonometry! I expect you all know this. The center distance of the pins on the sine bar are 5” apart, so to set the angle calculate the height of a stack of gauge blocks to put under the rear pin. Sin (5.572) X 5.0” is the calculation.
Enough waffle – pitchers here.





So then after touching the face of the end mill off on the top of the tooling ball (using a feeler gauge) it’s just a matter of raising the knee gradually and carving away the material.







Simple enough and quite satisfying.

2 parts down, lots more to go.

[crueby]

Great attention to detail!  I assume the purpose of that sloped end is to let condensate in the cylinder run down to a drain valve?

[propforward]

I think that is correct Chris - nothing is specifically included but the plans point to that location for a drain cock. If this were to only be run on air I guess that wouldn't matter too much, but running on steam is more fun! Hope to do that some day.

[propforward]

I made a video about this component, so it's here in case anyone is interested, complete with chapters so you can skip over things if you want.

It's a half hour and frankly is mostly discussion about how to do the geometry around the tooling ball and the angled surface, but I feel like there tends not to be an appreciation of that kind of thing in a lot of home shops. Well, anyway there it is.


<a href="https://www.youtube.com/watch?v=Voe0JZo1JEk" target="_blank">http://www.youtube.com/watch?v=Voe0JZo1JEk</a>

[propforward]

I made some bushings. Satisfying, but there isn't much to say about it. Nasty burr on the one which I need to polish off. Ho hum.

[55fairlane]

Your engine is coming alone nicely.....are those bushings brass or bronze?  And (because I'm kinda 'tupid) where do they go on this engine

[propforward]

Well, slowly slowly. These are the main bearing bushings for the beam pivot - and…….they are junk.

Following our convo yesterday I checked the bores and they are undersize. Did not expect that. I don’t know why reaming using flood coolant would cause that, but I’m going to make these again and re without flood coolant just to see if the bores come out on size.

I could try and re ream these, but I want to test the process. These are ugly anyway. Do over. Same bar, same reamer. See if the use of coolant vs oil makes a difference. You live and learn.

Another lesson - check the bore size before parting off.


I guess there was stuff to say after all.

[Michael S.]

But Stuart,
why make new bushings?
They look good. And a little smaller in the bore isn't so bad. You haven't made the shaft for the beam yet, have you?

Michael

[propforward]

Yes I can save these for sure - or make the shaft smaller - but I also want to understand why my reamer made an undersize hole. I’ve used that reamer before and made on size holes. So I want to investigate. That’s all really.

[Michael S.]

Yes, okay, Stuart.

Then the two bushings are for the first wear stage of the beam engine 😉.

Regards, Michael 

[propforward]

The biggest screw up here is that these should be split bushings.

[propforward]

It has been a bit, but I picked this engine up again. I suddenly got an urge to mess with the column.

I'm pretty sure this can be made successfully by simple layout techniques, as the sideways position of the beam can float a lot on the pivot. Still I think it's a good idea to make things as accurately as possible - meaning making sure geometry of features is appropriately aligned, so I spent plenty of time measuring the casting to see where the material sat relative to where the finished part has to be. In doing so I discovered that the square base did not have enough material in spots to clean up, and the same was true on the top platen. So I made a basic 3D model and changed a few dimensions to look at the impact of altering things a bit, and came up with a plan, which included measuring the mating entablature to make sure that would attach and be the same width. I was happy to see there was plenty of material to take off the sides of the column top to match the entablature width.

Model (not all features are modelled in)



Column and entablature





Measuring included a lot of this kind of thing - shimming one end and flipping back and forth between opposite sides and touching off just to see roughly how central the column is. What I established was that with a 1/8" shim under the small end, I can bring the base and top to size and clean off the base square and get some reference surfaces to work with.





So then it's a matter of transferring that to the mill and getting on with it. Doing the pre measuring gives me the confidence of defining a process to follow. The one part of this that will be a bit freeform is turning the actual tapered column and decorative features. That will be a case of basically turning to clean up and it is what it is - but the mounting features need to be accurate.



With all the measuring pre work it's very easy to take off the appropriate amount of material each side of the top and bottom fatures and get them to size - plus I know they are true and centered relative to each other, which will make it easy for me to get the beam bearings located so they will positioned correctly relative to the soleplate positions and therefore the cylinder and flywheel bearing positions.



At the same time I squared off the underside using this long end mill that I happened to have on hand (was given it by a machinist at a place I used to work. He gave me all his old HSS tooling as he no longer used it).

The trick here is very light cuts and several spring passes so that the underside stayed square. The underside is NOT to finished dimension at this stage. I'm leaving material so that I can adjust that and get the height correct after machining the bearing mounting surfaces.





Then a double check to make sure the dimension from each machined surface is correct, as well as being sure how to pack the part up for machining the opposite sides.



Setting up on gauge blocks (and before anyone gets offended I have a cheap and cheerful set specifically for clamping and then a nice set for measuring, and never the twain shall meet).



I know the position of the endmill by touching off on a 1-2-3 block and setting that position on the Z axis on the DRO (could do it with the wheel dials just as easily - maybe with a little more concentration needed and consideration of backlash).



Apparently I didn't take a picture of the finished sides after that bit of machining, which is as far as I got. With a bit of luck I'll get a bit of time this afternoon to keep going. So far about 90% measuring and planning, and 10% actual machining. Maybe less than that. But if I don't plan these things out this way I have a tendency to screw them up.

This part would actually be much easier to make from solid bar - one of the reasons I like castings is the extra challenge in work holding and then figuring out a plan.

I'll try not to leave it nearly a year until the next post. 

[propforward]

A little bit more needless handwringing:

Clamped against 2 blocks so that the base and one machined surface are held square, and sat down on a 1/8" gauge block so that the ring doesn't interfere with the surface plate. Then measured some high spots on the column. Then rotated the column 180° and did the same. The point being to establish how close to center the column is. It's about .010" off center at the largest diameter and a lot more at the smallest diameter. However from prior measurements it seems there's about 0.100" stock around it so should not be an issue, and the column part is not critical dimension wise, I just want to be able to machine it and not make it too skinny.



So then clamp it up and make sure the base is square to the table (and therefore vice), with appropriate packing.



Then touch off on the determined spot on the side of the base and machine it down (.082" removed).



Then zero the Z axis, and machine away the entablature mount faces to -.094" relative to the base surface.



Now I know that the entablature mount faces are square to the base, and if I maintain that relationship throughout the remainder of the process, then I won't suffer a drooping entablature. No one wants a droopy entablature.

One more side of the base to clean up, and then I'll turn attention to the top of the column. Maybe next weekend.

[55fairlane]

Looking good my friend.

Working with castings is its own specialty......45% of your time is spent laying the work, taking notes on much stock to remove/ leave on each feature  , 45% of the time its design & build a fixture  ....the other 10% is the machine time...

A final note on machining castings,  I tell guys there are 3 ways to do it, the way the textbook tells you, the wrong way & the way we do it on the shop floor.

Will this be ready for October?

Keep up,the good work

[MJM460]

Hi Stuart, good to see you back on the project.  It is an interesting one.

MJM460

[propforward]

Will this be ready for October?

Keep up,the good work

Thank you for your kind words! At the rate I’m going October is unlikely, with so many demands on my time. Hey ho. I’ll do a bit here and a bit there and see what happens. 👍

[propforward]

Hi Stuart, good to see you back on the project.  It is an interesting one.

MJM460

Thankyou. I’ve been making tooling and finishing other projects, and I’m very pleased to pick this up again.

[john mills]

did you ream before or after machining the groove in the bushes were the bushes have a burr the parting tool could have pushed the bush in  reducing the size of the hole
john

[Jasonb]

As for split bushings, our engines don't tend to get the amount of use that may require the bearings tightening up so I either make tham solid on small engines or on one this size make a split but do not unsolder them. Makes it easier to keep track of what goes where and if needed could always be split and adjusted in years to come.

[Chipswitheverything]

Just been enjoyably flicking back through the earlier postings on this beam engine build, and incidentally admiring your fine workshop set up. And the beefy and generous size milling machine, which is quite helpful in tacking a casting like the engine column. Taking a long series cutter right across the column base without chatter does test the solidity of the mill and vice capacity!

I'd say, from my experiences of making the Stuart Major Beam engine, written up here in the Forum, that the particularly careful attention that you are bringing to checking and accurately aligning all the machined elements of the column at top and bottom will pay off in your favour very well, and prevent a few headaches in later assembly.

I got away with a few things that , with hindsight, I might have been best to be very scrupulous over at the outset ...   The clearances of the moving parts, even at the bigger scale of the Major model, are surprisingly tight in places!  It's true that the beam itself can be slightly adjusted laterally on its shaft, but a nudge one way to help with the cylinder then has snags at the crankshaft end ...  Same goes for the various vertical dimensions which interact quite critically. So holding best accuracy throughout all the components is going to be worth the care that you are bringing to the build.  Dave

[propforward]

Dave - thank you. That is exactly how I feel about it - best effort here means a better outcome later - or should do. Incidentally your Stuart Major build was one of the reasons I chose to undertake a beam engine, albeit a slightly smaller one.

Jason and John - it was a while ago that I made those two bushings, but I bet you are correct - I suspect my parting off burred over the end. I'll have to revisit those. I have more bushings to make anyway. I won't split these yet, but will get back to those in due course. Simple enough to remake if I have to. I believe I reamed them out again and they came good.

Thanks everyone for looking in.

[Chipswitheverything]

Thanks Stuart : pleased to think that my beam engine helped to promote your enthusiasm for making a similar sort of engine! Somehow a beam engine seems to make a model that has strong visual appeal to many.

I'm playing around with the early stages of making the Stuart triple expansion engine, and trying to take a leaf out of my own book in what I was expressing in the post about checking and setting up ...  Starting now on some initial machining of the two castings for the cylinder blocks, and thinking about what datums to establish.
Years ago, I had no DRO on a mill, and using it was a big help in keeping the elements of the bedplate of the triple under control when I tackled that recently. I think, hope, that the same will apply to aspects of the cylinder machining.
 I'm rather aware that the triple could test the success or otherwise of the alignments and spacings of the many ( eventual ) moving parts in a very unforgiving way! Dave

[55fairlane]

I served my apprenticeship with no DRO.....I honestly would not want to try that again

[propforward]

A little more progress today.

I set the casting up on parallels in the vice, and having learned the hard way that a tall part can really move about quite a lot with no support higher up, rigged up the below arrangement.



The angle pieces were machined with a flat and a clearance through hole, and the ends of the studs got a little turned end to fit loosely in the through hole, with the effect that the angles can tip a bit to take up the taper of the column.



I had an indicator in place when tightening the side supports to make sure I wasn't deflecting the part.



This arrangement kept everything nicely supported, and I was still able to get in with a height guage and touch off on the parallels, thus getting accurate measurements during the machining.



Now, having machined the sides of the plinth accurately relative to the base, finding center was straightforward and it was just a matter of gently machining away to meet dimensions. I used a 1/4" end mill to keep loads down and just took light cuts.




The inner surface of the plinth is the least critical, but I completed that first to use it to establish dimension to ensure the bearing pads were correctly placed. Cutting direction was always parallel to the supports.







With that done it was a simple matter of drilling and tapping holes for the bearings (I am using all UNC or UNF just because I do not have any BA tooling) in this case 4-48.





Then I put in a counterbore, which will be used to hold a plug to properly support the part when turning the column. As you can see, the core is way off center. When complete, I will likely put a decorative brass plug in the hole.





I then inverted the column and repeated some of the process. Since the underside does not need any facing at this stage, only hole drilling, I did not need the side supports. I sat it on parallels and clamped it firmly. I did do a check with a square in both X and Y directions just to be sure everything was right.





While I had it set up, I put another counterbore in. I might use that for holding it in the lathe. I might not. It made sense to add it while I had the chance.



That brings us up to speed. I am happy with how this went - it was a very enjoyable process. I now need to make a couple of form tools for the radii on the column, and also at least one supporting plug before I can continue.

At some point I will also add some grooves to the sides of the plinth, but will wait until the entablature is done so I can match those decorative features to that.

[Sanjay F]

Looks great and I like the way you made the clamps and the whole setup looks very soild ...... following along with interest 

[Chipmaster]

You deserve an accurate column having taken so much care Stuart, surely your entablature won't droop or be off centre. 

Andy.

[Chipswitheverything]

Nice photos of the operations on the column.  Your belt and braces set up certainly ensured that nothing was going to misbehave!  I think that when I machined the top of my column, on a big Bridgeport mill at work, to get the height, I had machined the underside of the base and then clipped the casting down with four dogs to the table, so achieved rigidity that way. Dave

[propforward]

I thought about setting it up that way, but was still concerned about vibration and chatter on a relatively tall component. Then I did see your detailed thread, after I’d done this. 😁

I have a habit of over complicating these things, but this didn’t take long to set up and added some reassurance. The other thing was the vise was already accurately trammed so made that part of the set up very easy.

[propforward]

Not too much done today, but made progress on form tools and supports for the column.



Just made some light press fit plugs for each end, with a center drill location in the end for the revolving center.





So it goes in the lathe hard up against the jaws, with pressure applied through the revolving center - a genuine Daintree Tools item that I bought directly from Daintree in Australia. A very high quality piece of kit.



Hopefully will get some time to work on this during the week. We'll see - spring means yardwork and other stuff, so it might be a bit before I get to this. At least I'm ready to go.

[Michael S.]

 

[Roger B]

That was a clever setup to machine the top of the column     

[propforward]

I found some time today to work on the column some more. Haven't touched it in weeks. Too many non fun things going on.

Anyway, I used the taper attachment and kind of sort of matched it to a vague sort of average of the cast column taper, as a starting point, using an indicator. The cast taper isn't great of course, and since this is a more or less decorative feature I didn't stress about it too much.



Then started taking light cuts to see how it fared. Run out of the column was pretty severe.



Anyway, it didn't take too long to start cleaning up.



While I'm typing - here is a look at the rubber sheeting I put in place to keep iron dust from getting under the saddle. This seems to have worked out well. It's 3 pieces that overlap significantly. This is a bit of a lash up, but given how well it has worked I'll work on making some brackets for better attachment and easy install.



There was basically a lot of back and forth with some different tools. The thickness of the base was easy to establish, and also the underside of the top platen. The column decorative features were mostly just done to clean up and left where they ended up - although I did take some measurements to make sure I wasn't way off, but with the column running out so much the final dimensions aren't exactly what is on the original print, but I think it looks alright.



Going at the top bulge with a form tool:



And this is where I ended up. Some finishes are rougher than I wanted but will polish up satisfactorily. There is still a little finishing to do on some details in some places (corner radii and some diameters to reduce), but I was out of time. It's come along well though and I'm pretty happy with it.





This part would have been a LOT easier to turn from solid bar, but it has been an enjoyable challenge to work from the casting.

[john mills]

that looks good   remember the full size engines would have been a casting
it would bee a straight forward machining job on a cnc machine but i could not have done it on the mazes i used
they had no tail stock   although one nite the machine said the tail stock was in the way.
john

[propforward]

Very true - the full size would have been left as a casting. This was quite a ways off though so I wanted to make it look a little nicer.

I have seen many examples of these engines where the column is polished. That looks great I reckon, but I’ll be painting mine, so I won’t polish the column much more than needed to basically knock any burrs and rough spots off.

[crueby]

Nicely done!  And good practice for turning out a metal chess set...   

[propforward]

Ha! Yes indeed! 😂

[Michael S.]

Hi Stuart,

I really like the column. You did a great job.
I’m going to paint the column on my Beam later on, too.

Michael

[Chipswitheverything]

That looks fine, and will paint up nicely.  I'd been a bit disappointed when the larger column of my ST Major Beam refused to turn to a uniform finish that would polish up evenly , it had a lot of flecking and some small blowholes in the metal.  But I think now that the painted finish of it is in fact preferable, and certainly more in keeping with the prototype engine.

[propforward]

Thanks everyone for looking in and for your comments. I’m enjoying this, even if it is progressing more slowly than continental drift. 😁

[Jasonb]

Sometimes fully machining is the only way to get a decent looking part

Remember full size were cast

This is true but we need to take into account that sand does not scale, lets say the original was cast with 100grit size sand at 1/12th scale that will be 1200g so the finish would not show any sand texture but most model foundries use the same sand whatever the part.

Also mould shift and parting lines do not scale. So if the model had the two halves out by 1/32" then that is like 3/8" on fill size, same for any flash around the joint line.

[propforward]

I posted a video of the column turning. If you’re an insomniac it might help you get to sleep. 😁

<a href="https://www.youtube.com/watch?v=1bhAp4Y_Emk" target="_blank">http://www.youtube.com/watch?v=1bhAp4Y_Emk</a>